Movie touts desperate for a winner may be forgiven for pinning such high hopes on Seabiscuit. It is, after all, a rare pedigreed entrant in a summer of mules, sired by writer-director Gary Ross out of Laura Hillenbrand’s marvelous best-seller about a horse born to lose who ended up winning at a time in America’s history when the little guy was in desperate need of a hero who beats the odds.

The bay himself, descended from Man o’ War, was knobby-kneed and unruly — the legacy of beatings and neglect. His owner, Charles Howard, was a self-made auto dealer with sadness in his life and a fondness for underdogs. Seabiscuit’s trainer, Tom Smith, was a taciturn loner, a cowboy more at home with animals than people. And his jockey, Red Pollard, was a scrappy brawler, abandoned when he was a boy, too tall for his profession, and blind in one eye.

Set during the Great Depression and starring wounded men and a wounded horse who get back on their feet after life knocks them down, the story of Seabiscuit would make a beauty of a movie even if it were invented by screenwriters. That the tale is true only sweetens the victory and raises the stakes. And Gary Ross — the writer of ”Big” and ”Dave,” the director who re-created an iconic 1950s America in ”Pleasantville,” a lover of horse racing and politics — knows all this: He aims his movie at a more mature, more discerning audience than the ”Charlie’s Angels” crowd, and employs Tobey Maguire as Red Pollard not so much because the grave, recessive young actor did superhero box office business in ”Spider-Man” but because he played a grave, recessive young man in ”Pleasantville.”

”Seabiscuit” trembles with respect for Hillenbrand’s book. It’s hobbled by good intentions, grand plans for telling many stories at once, and a fear of the very audience whose intelligence and sophistication it claims to court — otherwise, why stick so rigidly to the conventions of the square and uplifting when it comes to adapting prestigious literature? If anything, Ross takes the ringing, ”Rocky”-style American lessons about the common man and the noble horse implied in the fable too much to heart, then passes them along to us with such overemphasis that there’s nothing for us to discover for ourselves. Even exciting racing scenes — the main event, after all, filmed with a feel for speed by cinematographer John Schwartzman — are schoolmarmishly interrupted by archival still photographs of Americans, rich and poor, following the action on that great unifying medium, the radio.

As if he feared that a handsomely shot movie about men and a horse who defied defeat together wouldn’t be moving enough, Ross has turned his ”Seabiscuit” into something less passionate and more hortatory: a Ken Burns-earnest essay about the character of America, speeches and all. And such speechifying! Historian David McCullough — as identifiably the voice of important public-TV productions as Walter Cronkite was once the voice of important network news — narrates a historical overview that reads like plain poetry in Hillenbrand’s pages, but assumes a far more good-for-you tone in voice-over. ”It was the beginning and the end of imagination,” McCullough orates, describing the cataclysmic changes wrought by the introduction of the assembly line that built the Model T. (The accompanying score by Randy Newman reinforces that sentiment with swaths of Aaron Copland chords blended with bits of homespun-by-Ralph Lauren Americana.)

Jeff Bridges handles the elements of manly maturity and can-do risk taking, playing Howard with the same reassuring self-confidence that made him such a fine car guy — and capitalist with a dream — once before, in ”Tucker.” ”Where can’t we go in America? The sky is literally the limit!” a buoyant Howard declares before his personal life takes a plunge. Meanwhile, the folksy speeches exemplifying quiet respect for animal instinct go to Chris Cooper as trainer Smith. Samples: ”He’s forgotten what he’s born to do. He just needs to be a horse again.” Also, ”Every horse is good for somethin’.” (We know less about Smith than we do about anyone else; Cooper, a model of self-effacement, does some of his best work consulting a stopwatch at the track.)

Part of Ross’ challenge is that both Smith and Pollard are such inward, contained men that the actors playing them have got to work with the energy of absence rather than presence. And in this, Maguire uses his natural wariness like an all-purpose tool. Slimmed down and sinewy, his crimped and dyed hair setting off the pallor of his skin, his Red is a study in negative spaces. Yet when he’s on a horse, Maguire becomes a different, energized animal — and the whole movie surges ahead.

In a small and intrusively shtick-filled fictional role, fellow ”Pleasantville” alumnus William H. Macy plays a tippling radio announcer whose on-air burbling helps hype this legendary horsey-interest story and drum up wagers. A lot of moviegoers have been betting on ”Seabiscuit” to win. Will you settle for show?